feat(Calendar): add new clear method

Closes #188

BREAKING CHANGE: Calendar's `clear()` method is a completely new implementation and, unlike previous versions, will not reset metadata such as `name` or `prodId`. Only the events will be removed

src/calendar.ts

@@ -294,7 +294,6 @@ export default class ICalCalendar {
      * that have already been added are retained.
      *
      * @since 0.2.0
-     * @returns {ICalEvent[]|ICalCalendar}
      */
     events(): ICalEvent[];
     events(events: (ICalEvent | ICalEventData)[]): this;
@@ -308,6 +307,18 @@ export default class ICalCalendar {
     }
 
 
+    /**
+     * Remove all events from the calendar without
+     * touching any other data like name or prodId.
+     *
+     * @since 2.0.0-develop.1
+     */
+    clear(): this {
+        this.data.events = [];
+        return this;
+    }
+
+
     /**
      * Save ical file with `fs.save`. Only works in node.js environments.
      * If no callback is specified, `fs/promises` is used and a promise is returned.

test/calendar.ts

@@ -314,6 +314,16 @@ describe('ical-generator Calendar', function () {
         });
     });
 
+    describe('clear()', function () {
+        it('should do the job', function () {
+            const cal = new ICalCalendar();
+            cal.createEvent({});
+            assert.strictEqual(cal.events().length, 1);
+            assert.deepStrictEqual(cal.clear(), cal);
+            assert.strictEqual(cal.events().length, 0);
+        });
+    });
+
     describe('save()', function () {
         it('should return all public methods and save it', function (done) {
             const file = join(__dirname, 'save.ical');